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<FONT color="green">001</FONT>    // Copyright 2007 Waterken Inc. under the terms of the MIT X license<a name="line.1"></a>
<FONT color="green">002</FONT>    // found at http://www.opensource.org/licenses/mit-license.html<a name="line.2"></a>
<FONT color="green">003</FONT>    package org.waterken.serial;<a name="line.3"></a>
<FONT color="green">004</FONT>    <a name="line.4"></a>
<FONT color="green">005</FONT>    import static org.ref_send.promise.Eventual.cast;<a name="line.5"></a>
<FONT color="green">006</FONT>    <a name="line.6"></a>
<FONT color="green">007</FONT>    import java.io.Serializable;<a name="line.7"></a>
<FONT color="green">008</FONT>    import java.util.Iterator;<a name="line.8"></a>
<FONT color="green">009</FONT>    <a name="line.9"></a>
<FONT color="green">010</FONT>    import org.ref_send.promise.Deferred;<a name="line.10"></a>
<FONT color="green">011</FONT>    import org.ref_send.promise.Eventual;<a name="line.11"></a>
<FONT color="green">012</FONT>    import org.ref_send.promise.Promise;<a name="line.12"></a>
<FONT color="green">013</FONT>    import org.ref_send.promise.Resolver;<a name="line.13"></a>
<FONT color="green">014</FONT>    <a name="line.14"></a>
<FONT color="green">015</FONT>    /**<a name="line.15"></a>
<FONT color="green">016</FONT>     * A {@link Series} maker.<a name="line.16"></a>
<FONT color="green">017</FONT>     * @see "Section 19.9 'Queues' of 'Systems Programming in Concurrent Prolog';<a name="line.17"></a>
<FONT color="green">018</FONT>     *       Concurrent Prolog Collected Papers Volume 2; Ehud Shapiro; 1987."<a name="line.18"></a>
<FONT color="green">019</FONT>     */<a name="line.19"></a>
<FONT color="green">020</FONT>    public final class<a name="line.20"></a>
<FONT color="green">021</FONT>    Serial {<a name="line.21"></a>
<FONT color="green">022</FONT>        private Serial() {}<a name="line.22"></a>
<FONT color="green">023</FONT>    <a name="line.23"></a>
<FONT color="green">024</FONT>        /**<a name="line.24"></a>
<FONT color="green">025</FONT>         * Makes a {@link Series}.<a name="line.25"></a>
<FONT color="green">026</FONT>         * @param _ eventual operator<a name="line.26"></a>
<FONT color="green">027</FONT>         */<a name="line.27"></a>
<FONT color="green">028</FONT>        static public &lt;T&gt; Series&lt;T&gt;<a name="line.28"></a>
<FONT color="green">029</FONT>        make(final Eventual _) {<a name="line.29"></a>
<FONT color="green">030</FONT>            /*<a name="line.30"></a>
<FONT color="green">031</FONT>             * The implementation starts with a promise for the initial element,<a name="line.31"></a>
<FONT color="green">032</FONT>             * from which all other promises are derived.<a name="line.32"></a>
<FONT color="green">033</FONT>             */ <a name="line.33"></a>
<FONT color="green">034</FONT>            final Deferred&lt;Element&lt;T&gt;&gt; initial = _.defer();<a name="line.34"></a>
<FONT color="green">035</FONT>            class SeriesX implements Series&lt;T&gt;, Serializable {<a name="line.35"></a>
<FONT color="green">036</FONT>                static private final long serialVersionUID = 1L;<a name="line.36"></a>
<FONT color="green">037</FONT>    <a name="line.37"></a>
<FONT color="green">038</FONT>                protected Element&lt;T&gt; front_ = cast(Element.class, initial.promise);<a name="line.38"></a>
<FONT color="green">039</FONT>                private   Resolver&lt;Element&lt;T&gt;&gt; back = initial.resolver;<a name="line.39"></a>
<FONT color="green">040</FONT>    <a name="line.40"></a>
<FONT color="green">041</FONT>                public Iterator&lt;Promise&lt;T&gt;&gt;<a name="line.41"></a>
<FONT color="green">042</FONT>                iterator() {<a name="line.42"></a>
<FONT color="green">043</FONT>                    class IteratorX implements Iterator&lt;Promise&lt;T&gt;&gt;, Serializable {<a name="line.43"></a>
<FONT color="green">044</FONT>                        static private final long serialVersionUID = 1L;<a name="line.44"></a>
<FONT color="green">045</FONT>    <a name="line.45"></a>
<FONT color="green">046</FONT>                        private Element&lt;T&gt; current_ = front_;<a name="line.46"></a>
<FONT color="green">047</FONT>    <a name="line.47"></a>
<FONT color="green">048</FONT>                        public boolean<a name="line.48"></a>
<FONT color="green">049</FONT>                        hasNext() { return true; }  // The future is unlimited.<a name="line.49"></a>
<FONT color="green">050</FONT>    <a name="line.50"></a>
<FONT color="green">051</FONT>                        public Promise&lt;T&gt;<a name="line.51"></a>
<FONT color="green">052</FONT>                        next() {<a name="line.52"></a>
<FONT color="green">053</FONT>                            /*<a name="line.53"></a>
<FONT color="green">054</FONT>                             * Produce a promise for what will be the value of the<a name="line.54"></a>
<FONT color="green">055</FONT>                             * current element and hold onto an eventual reference<a name="line.55"></a>
<FONT color="green">056</FONT>                             * for what will be the next element in the list, which<a name="line.56"></a>
<FONT color="green">057</FONT>                             * is now the current element in the iteration order.<a name="line.57"></a>
<FONT color="green">058</FONT>                             */<a name="line.58"></a>
<FONT color="green">059</FONT>                            final Promise&lt;T&gt; r = current_.getValue();<a name="line.59"></a>
<FONT color="green">060</FONT>                            current_ = current_.getNext();<a name="line.60"></a>
<FONT color="green">061</FONT>                            return r;<a name="line.61"></a>
<FONT color="green">062</FONT>                        }<a name="line.62"></a>
<FONT color="green">063</FONT>    <a name="line.63"></a>
<FONT color="green">064</FONT>                        public void<a name="line.64"></a>
<FONT color="green">065</FONT>                        remove() { throw new UnsupportedOperationException(); }<a name="line.65"></a>
<FONT color="green">066</FONT>                    }<a name="line.66"></a>
<FONT color="green">067</FONT>                    return new IteratorX();<a name="line.67"></a>
<FONT color="green">068</FONT>                }<a name="line.68"></a>
<FONT color="green">069</FONT>                <a name="line.69"></a>
<FONT color="green">070</FONT>                public Element&lt;T&gt;<a name="line.70"></a>
<FONT color="green">071</FONT>                getFront() { return front_; }<a name="line.71"></a>
<FONT color="green">072</FONT>    <a name="line.72"></a>
<FONT color="green">073</FONT>                public void<a name="line.73"></a>
<FONT color="green">074</FONT>                produce(final Promise&lt;T&gt; value) {<a name="line.74"></a>
<FONT color="green">075</FONT>                    /*<a name="line.75"></a>
<FONT color="green">076</FONT>                     * Resolve the promise for the last element in the list with an<a name="line.76"></a>
<FONT color="green">077</FONT>                     * actual element containing the provided value, and an eventual<a name="line.77"></a>
<FONT color="green">078</FONT>                     * reference for what will be the next element in the list,<a name="line.78"></a>
<FONT color="green">079</FONT>                     * which is now the new last element.<a name="line.79"></a>
<FONT color="green">080</FONT>                     */<a name="line.80"></a>
<FONT color="green">081</FONT>                    final Deferred&lt;Element&lt;T&gt;&gt; x = _.defer();<a name="line.81"></a>
<FONT color="green">082</FONT>                    back.apply(Link.link(value, cast(Element.class, x.promise)));<a name="line.82"></a>
<FONT color="green">083</FONT>                    back = x.resolver;<a name="line.83"></a>
<FONT color="green">084</FONT>                }<a name="line.84"></a>
<FONT color="green">085</FONT>    <a name="line.85"></a>
<FONT color="green">086</FONT>                public Promise&lt;T&gt;<a name="line.86"></a>
<FONT color="green">087</FONT>                consume() {<a name="line.87"></a>
<FONT color="green">088</FONT>                    /*<a name="line.88"></a>
<FONT color="green">089</FONT>                     * Produce a promise for what will be the value of the first<a name="line.89"></a>
<FONT color="green">090</FONT>                     * element and hold onto an eventual reference for what will be<a name="line.90"></a>
<FONT color="green">091</FONT>                     * the next element in the list, which is now the first element.<a name="line.91"></a>
<FONT color="green">092</FONT>                     */<a name="line.92"></a>
<FONT color="green">093</FONT>                    final Promise&lt;T&gt; r = front_.getValue();<a name="line.93"></a>
<FONT color="green">094</FONT>                    front_ = front_.getNext();<a name="line.94"></a>
<FONT color="green">095</FONT>                    return r;<a name="line.95"></a>
<FONT color="green">096</FONT>                }<a name="line.96"></a>
<FONT color="green">097</FONT>            }<a name="line.97"></a>
<FONT color="green">098</FONT>            return new SeriesX();<a name="line.98"></a>
<FONT color="green">099</FONT>        }<a name="line.99"></a>
<FONT color="green">100</FONT>    }<a name="line.100"></a>




























































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